The present invention refers to sports footwear which can for instance be used for skates with in-like rollers, boots for cross-country skiing and snowboarding, as an inner component part of a ski boot, and the like.
In sports practices of this kind, the foot is subject to repeated bendings of the ankle, whereas the heel must remain steadily firm and locked in the proper seat in the footwear. Accordingly, it is a basic pre-requisite of such a kind of footwear to be constructed in such a manner as to both favour a bending of the ankle and spare the user such dangerous mishaps as muscular sprains or even simply undesirable side-effects such as foot movements that appear to be scarcely polished and/or of a scarce effeciency when practicing the sport activity.
U.S. Pat. No. 4,505,056 discloses a sports footwear which is particularly suitable for cross-country skiing applications and is substantially constituted by an outer shell made of a rigid polymeric material and by an inner shoe that is removable from the outer shell and is made of a soft, flexible polymeric material, such as for instance foamed polyurethane. Both the outer shell and the inner shoe comprise, as an integral, single-piece injection-moulded part, a sole and an upper. The upper of the outer shell is provided, further to a transverse fastening clip, with first downward cutouts extending below the ankle in correspondence with the instep, and second cutouts extending as far as the sole at the level of the metatarsus. The upper of the inner shoe in turn comprises: a relatively thin and compact rear portion associated to a padding with another transverse fastening clip, which rises up within the outer shell above the ankle; a relatively thick and compressible front portion that extends within the outer shell to reach the toe of the footwear; an intermediate portion, which is also relatively thick and compressible and covers the top of the foot. In correspondence of said second cutouts of the upper of the outer shell, the upper of the inner shoe is therefore exposed to view and provided with some transverse grooves intended to facilitate the metatarsal bending of the foot.
This footwear is anyway quite complex in its construction, especially as far as the parts of differing thickness of the inner shoe are concerned. Furthermore, it is quite obviously subject to penetration of water and/or snow at the locations where the upper of the same inner shoe is exposed.
It would on the contrary be desirable, and is actually a main purpose of the present invention, to provide a footwear of the above illustrated kind that, further to complying with the afore indicated pre-requisite in the best possible manner, is also capable of being manufactured industrially on a large scale in a simple manner and at low costs.
Another well-known kind of footwear construction comprises a lower shell and a upper shell provided with a rear door, that is hinged according to a transverse axis arranged in the zone of the heel, for the foot to enter the footwear, as well as an insert of elastic material and an associated padding element that are accommodated between the lower shell and the upper shell, in front of the instepxe2x80x94see U.S. Pat. No. 4,095,356. However, such a construction is only partially capable of meeting the afore mentioned pre-requisite, since it not only needs a rigid shell, but also an equally rigid leg-portion to compress the elastic insert to an adequate extent during the controlled forward deflections of the shell. Actually, this is true and needed only in the case of footwear items, i.e. boots for downhill skiing, where structural rigidity of the footwear is a must. It shall further be duly borne in mind that a risk always exists for the insert and/or padding element to be lost, in which case they can actually be going to be replaced with other parts that may be differently sized and/or be made of different material so as to result in different bending characteristics of the footwear.
Similar considerations can also be made in connection with another prior-art footwear constructionxe2x80x94as disclosed in U.S. Pat. No. 5,819,441xe2x80x94in which an element of a viscoelastic material adapted to dampen shocks is arranged in the top zone of the footwear, although such an element is actually subject to shear stress rather than compression stress.
A footwear provided with at least one elastically deformable element that is an integral, non-removable part of a flexible shoe, enables not only to meet the above cited pre-requisite, but even to achieve other objects.
Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while Indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.